When manufacturing paper the machine reel, so called tambour reel, made by the paper machine and having the width of the paper machine, is cut by the slitters to customer reels, whose width and length or diameter is desired. The machine reel has a width and a diameter that is in accordance with the dimensioning of the paper machine. During the slitting the machine reel is reeled off, is slit to webs with desired width and the webs are reeled on the customer rolls that have the length and width according to the order. The finishing machine reels are generally controlled by frequency converter drives, or by other controllable devices wherein the drive motors controlling frequency converters control the rotation speed of the motors according to the given control parameters so that the completed customer rolls fulfill the requirements of the end user or upgrading as regards to their outer overall dimensions and their inner structure.
Typically, the customized rolls are reeled by the slitter and the widths and lengths the customized rolls are varying according to the orders. It is characteristic of the paper manufacture that the manufacturing process is continuous and it is not possible to create a large intermediate storage for unfinished products without interruption of the process or without slowing down the process. The slowest part of the process and the production chain determines thus the total speed of production and the capacity of the factory.
The slitting is a factor of essential importance as a point of view of the efficiency and smoothness of the production and its plan and implementation has been paid attention. The changeover time of the finished rolls is tried to decrease and the efficiency of the production is tried to upraise. Earlier e.g. control methods are known, whereby the reels are controlled to stop as exact as possible in order to achieve the desired length of the web or the desired diameter of the roll. According to the general principle known earlier the acceleration and the deceleration are chosen according to the pre-calculated worst situation without dependence on temporary parameters.
In connection of the conventional paper machine drives the dimensioning values of the paper machine are used as a defining control variable. Thus the highest allowable speed or acceleration of the reel are defined on the basis of the design values of the paper machine, wherein the defining factor is the required power that must be able to achieve but that must not be exceeded.